Impulse-coupling



W. E. SCHWARZMANN AND C. F.TOREN.

IMPULSE COUPLING. APPLICATION FILED DEC.8. 1919.

Patented Oct. 11,

(gar/9; 72/677 ATTORNEY.

UNITED STATES WOLFGANG E. SCHWARZMANN, 0F LONGMEADOW, SPRINGFIELD, MASSACHUSETTS, ASSIGNORS T0 PATENT OFFICE;

AND CHARLES F. TOREN, OF AMERICAN BOSCH MAGNETO YORK.

IMPULSE-COUPLING.

Application filed December 8, 1919. Serial No.

T 0 all whom it may concern Be it known that we, lVoLroANo E. SCHWARZMANN and CHARLES F. TOREN, citi- Zens of the United States, residing at and whose post-office addresses are, respectively, 51 Belleclaire avenue, Longmeadow, and 172 North Main street, Springfield, in the county of Hampden and State of ll'lassachusetts, have invented certain new and useful Improvements in Impulse-Couplings; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which use the same. i

The present invention relates to couplings wherein, at low speed, the driven device is locked against rotation until at a predetermined advance of the driving device it is impelled by the impelling spring at a comparatively high speed, and wherein, at higher speed, the locking mechanism is inoperative to thereafter ermit uninterrupted rotation of the driven .evice without appreciable retardation. Such mechanism is applicable to various kinds of rotatable devices which are not self-starting or self-driven, biitparticularly to magnetos for generating ignition voltages suitable for igniting a gaseous mixture present in a cylinder of the engine with which it is associated when the engine is being turned at low speed in starting or is stopping under load.

Many of the devices to which impulse couplin s are applicable may require rotation of tfie driven device in one direction or the other; 'for instance, some engines require clockwise rotation of the magneto while others require anticlockwise rotation. Prior forms of impulse couplings of the centrifugal type are adapted for rotation in one direction only, the conditions imposed by different engines-being met by using reversing gears, or by providing different right and left hand parts for the coupling. In accordance with this part of our invention, the use of reversing geais, or dift'erent right and left hand parts, -is avoided by making the impulse coupling itself reversible (notwithstanding that it is of the centrifugal type), so that it can be readily adapted for rotation in one direction or the other merely by changing the relative posiimpulse Specification of Letters Patent.

it appertains to make andv Patented Oct. 11, 1921. 343,297.

tion of certain of its parts to suit the exigencies of the different driving In the specific embodiment of the impulse coupling of the centrifugal type hereinafter disclosed in association with an enginedriven magneto, the abutment with which the centrifugally-responsive element periodically cooperates to lock the magneto against rotation while the engine is rotating slowly, is fixed on one seat for one direction of rotation, and on another seat for rotation in the reverse direction, so thatythe magneto is lockedprior to being impelled afterthe predetermined advance of the engine, is snapped through that position at a speed siifliciently high to generate an ignition voltage suitable for producing a satisfactory spark in the working stroke of'the cylinder to be fired. lVhere a spiral spring is used as the impelling spring of the coupling, as hereinafter shown, reversing the direction of rotation of the coupling necessitates reversing the spring.

n the impulse coupling hereinafter specifically disclosed, the centrifugally-responsive means for periodically locking the driven device for the subsequent impelling movement after the predetermined advance of the driving device, consists of transverselyslidable means adapted at low speed to fall by gravity into engagement with an abutment, and at higher speed to move transversely in the opposite direction in response to centrifugal force to an inoperative position. Whether the centrifugally-responsive means comprises two transversely-slidable elements, as shown hereinafter, or any other number, and one or more abutments coop erative therewith, the coupling is adapted to lock the driven device more than once per rotation. Thus, in application to a magneto, each one of the two or more ignition periods per rotation is made available for firing the engine in starting or stopping. By using slidable elements each located entirely on one side of the axis of rotation, the entire mass of each is subjected to centrifu; gal force in a single direction, so that none of them has to have a mass greater than that required to withstand the impact upon lock ing the driven device.

the destruction of the con We have found that impulse couplings of the centrifugal type are liable to destruction after the impelling spring breaks and before the engine comes to rest. This condition results from the fact that the driven member becomes relocked immediately after being released, since the broken spring does not then impel it from looking position, whereupon certain-parts of the coupling attached to' the driving and driven members come abnormally into engagement while the driving shaft is being turned and the driven shaft is locked. irrespective of the number, form and movement (whether swinging or slidable) of the centrifugally-responsive elements, the invention comprehends, as another of its parts, means adapted to prevent ling after the impelling spring breaks. referably the construction and arrangement is such that the centrifugally-responsive element or elements are retained in inoperative relation with the abutment, the driving and driven devices then rotating as a unit. in the specific embodiment hereinafter disclosed, this result is attained by means of a pin carried by one member of the coupling and adapted to engage a part of the other member in such angular position of the members that the releasing mechanism retains the locking element or elements in released position. By providing two seats for this pin, its proper relation with the cooperative part can be provided for both directions of rotation of a reversible coupling.

Whether or not the impulse coupling is of the centrifugal type, the invention comprehends, as another of its parts, adjustable means for fixing in relation to the coupling the support carrying the abutment of the locking mechanism. Ordinarily the abutment is carried by or is a part of a plate rigidly fastened to the driven device, the impulse coupling rotating in close proximity to the plate. Due to irregularities and inaccuracies in quantity production, the abut ment does not always attain the proper relation to the locking element that rotates with the coupling, and the coupling does not always have the proper clearance over the entire surface of the plate. In such cases, the periodic locking operation may not be satis. factory, and it may be difficult to prevent the entrance of foreign matter between the coupling and the plate. In accordance with the preferred embodiment hereinafter disclosed,

having a plurality these difiiculties are overcome by providing adjustableposts for supporting the plate carrying the abutment. .Preferably, these posts are individually adjustable in length by forming each of a stud with an extension screwed into it to the depth required, and 7 of nuts adapted to lock it in adjusted position of the stud.

The abutment must withstand the re- 2 is keyed the rename peated blows of the driving device in periodically locking the driven device. We have found that, to withstand the sheaiing and other stresses resulting from the force of these impacts, the abutment should be supported in such manner as to distribute the stresses to the plate or other member supporting it, whet-her the plate is in fixed or adjustable position. In the preferred embodiment hereinafter disclosed, the abutment is in the form of a. segment with a plurality of legs, preferably two terminal legs, entering slots in the plate so as to transmit the stresses resulting from the impact to the plate at a plurality of places. ln order that the legs may reliably abut all the receiving surfaces of the plate, we provide the plate with an elongated slot through which a screw passes into the abutment, whereby, if necessary, the abutment may be adjusted for this purpose. By providing the plate with a second elongatet slot and suitable slots for the reception of the legs, when the abutment is located for rotation in the reverse direction, the advantages of the construction are realized in a reversible coupling.

In the accompanying drawings illustrating the preferred form of an impulse coupling in application, as an example, to a reversible coupling of the centrifugal type in association with an engine-driven magneto generating two sparks per rotation, and also illustrating a modified form of supporting plate for-the locking abutment thereof.

igure 1 is a view showing the coupling, partly in central section and partly broken away, and showing the magneto in side elevation; Figs. 2, 3 and 4 are sections on lines 2-2, 3-3 and 4-l, respectively, of Fig. 1; Fig. 5 is an elevation of the driving disk between the impulse coupling and the engine-driven shaft; Fig. 6 is a perspective view of one of theslidable locking elements; Fig. 6 is a perspective view of the locking abutment; Figs. 7, 8, 9 and 10 are diagrammatic views showing the relation of the parts at different periods of a cycle; Fig. 11 is a. section, partly broken away, similar to Fig. 2 but showing the parts arranged for rotation in the reverse direction; and Fig. 12 shows a modified form of supporting plate for the locking abutment.

The magneto l is of any era-ting, in this case, two i nition voltages per rotation at 180 interva s. On its shaft driven member 3 of the im having a hub4, a rear wall suitable type genpulse coupling '5 and a rim 6. The driving member 7 of the coupling has a hub 8 journale-d at 9 on the hub 4 of the driven member and also having a front wall 10 with a partial rim 11', forming with thedriven member a cavity inclosing various parts of the coupling. Both the driving and the driven members are held axially on the shaft 2 by the nut 12, while the driving member has two radial tongues 13 fitted within complementary slots of a connecting disk 14. The other face of that disk has other radial slots for receiving the radial tongues 15 of a coupling 16 which is fast on the shaft 17 driven by an internal combustion engine.

The metal stamping 18 is fastened to the rim 6 of the driven member, and the hub 8 of the driving member has a saw cut at 19 so that the spiral impelling spring 20, having its outer end bent around one end of the stamping and its other end inserted in the saw cut, resiliently connects the driving and driven members of the impulse coupling. That spring is located in proximity to the front wall 10 of the drivingmember and is closed in that space by the loose washer 21. For rotation of the impulse coupling in clockwise direction as shown in Fig. 2, the convolutions of the spring extend in an anticlockwise direction, from its inner end in the saw cut to its outer end around the stamping. For rotation in anticlockwise rection, the spring is turned over so that its outer end clamps around the other end of the stamping and the convolutions extend in a clockwise direction, as shown in Fig. 11.

In the remaining space of the cavity are two locking elements 22, each generally of arcuate form extending entirely on one side of a plane through the axis of rotation of the shaft 2. Furthermore, each locking ele ment has an inwardly directed cam 23. and also a nose 24extending loosely through a radial slot at 25 in the rear wall 5 of the driven member so as to be movable freely in a radial direction between the innermost position shown at the top of Fig. 1 and the outermost position shown at the bottom of Fig. 1. The cams 23 of the two locking elements,v and also the noses 24 thereof, are 180 apart. An abutment 26, constituting the other element of the locking mechanism, is fastened to the stationary supporting plate 27 in position to be engaged by either nose 24 when, due to gravity, that looking element falls to its be cleared thereby when, due to centrifugal force, it retains its outermost position. The two releasing cams 28, projecting axially from the end of the hub 8 of the driving member, are adapted to simultaneously engage the two cams 23 and thereby move the locking elements outwardly to such position that their noses 24 are radially beyond the abutment 26.

In the form shown in Figs. 1, 2, 3, and 4, the supporting plate 27 is flat, and is rigidly fixed at each corner to the magneto frame by four posts each consisting of a stud 29 into which is threaded a screw 30 to an adjusted depth. The nuts 31 lock the screw at the depth to which it is adjusted in the post, so that the supporting plate 27 may be innermost position, and to properly positioned with respect to the coupling to compensate. for any inaccuracy in manufacture or alinement. In this way, the nose 24 of each locking element may be made to reliably engage the abutment 26 and the felt ring 32 prevents the entrance of foreign matter into the coupling through the slots 25.

In Fig. 12 there is shown a modification in which the supporting plate 33 has two bent legs 34 taking the plate of the two posts of the preferred embodiment previously described, the other two corners of the plate being supported at a fixed distance from the magneto by posts 35. This supporting plate is intended to be used where the. accuracy of. ma'nufacture and alinement normally produces reliable engagement of the locking mechanism and prevents the passage of foreign matter past the felt ring.

Irrespective of which of the two previously described forms is used. the supporting plate has three slots. of which 36 and 38 are similar. and 37. intermediate the other two, is of greater angular extent. The abutment 26 terminates in two depending legs 39, and is fastened to the supporting plate by a screw 40 passing into screw-threaded engagement with it through an elongated opening at 41 in the plate. lVhen the abutment is seated on the plate in the position shown in Fig. 4 for clockwise rotation of the impulse coupling, the two depending legs enter the slots 36 and 37. y means of the elongated opening at 41, the abutment may be adjusted until both of its legs contact with the receiving surfaces of those slots. F or anticlockwise direction, as shown in Fig. 11, the depending legs 39 enter the slots 37 and 38, and are positioned in contact with the receiving surfaces by means of the elongated opening 42 through. which the screw 40 passes to seat the abutment on the supporting plate in that position. Thus, whether the impulse coupling is arranged for clockwise or anticlockwise rotation, the blow received by the abutment in locking the ma neto against rotation, while the shaft 17 is rotating slowly, is distributed to the supporting plate at two separated places by the two depending legs 39.

The front wall 10 of the driving member has two depressions at 43 and 44, into either of which is adapted-to be seated a pin 45. For the direction of rotation that the coup ling is adapted, the pin is so located that it advances-nearly into engagement with the end of spring 20 that is looped around the stamping 16, when the driven memberis locked against rotation while the driving member is rotating slowly. At that position, however, the releasing cams 28 are in engagement with the cams 23, holding both locking elements in outermost position with the nose 24 of each beyond the abutment 26 (See Fig. 8). If the impelling spring 20 should be broken, so that the driven member is not impelled thereby from its locking osition, when released, further movement of the driving member brings the pin 45 into 5 engagement with the end of the spring, the

releasing cams still holding the locking elements in their outermost position free from the abutment. The driving and driven members of the impulse coupling then rotate freely as a unituntil the engine comes to rest, the magneto then being greatly retarded.

It will be understood that if the pin 45 were not provided, the locking element wouldreengage the abutment as soon as the releasing cams 28 passed the cams 23, so that, upon further movement of the driving member, the partial rim 11 would come into engagement with the end of the spring 20 clamped around the end of the stamping 18, whereupon, the driving member being locked, the coupling would be destroyed.

The operation of the impulse coupling in clockwise direction is illustrated diagrammatically in Figs. 7 to 10, the parts being arranged as shown in Figs. 1 to 4. While the engine shaft 17 is rotating slowly, either in being started or in stopping under load, cen- K trifugal force, due to rotation, is insuflicient to overcome the action of gravity on the locking elements, so that as each locking element is brought above the axis of rotation, it falls by gravity to its innermost position. The driven member is driven through the impelling spring until the nose 24c of that locking element comes into engagement with the abutment 26. This position is shown in i". The driven member is now locked against rotatign, and as the driving member continues to rotate, it winds up the spring 20 until the releasing oams28 engage the cams 23 to push the locking elements radially outward to a released position, as shown in Fig. 8. The nose 23 of the upper locking element now being clear of the abutment 26, and the impelling spring being stressed as a result'oi the relative angular displacement of the members, the driven member is impelled through the angle repre senting the previous angular advance of driving member during the period in which the driven member is locked. This position. is shown in Fig. 9, in th inipelling move ment, t 'ie n'iagneto is driven atlcompara tively hi h speed through its periotjot manimum gen ,tion. the ignition spark,

' plug which the operation und 1. o SilOl depending legs enter assa/es after the locking elements are retained in their outermost position, as shown in Fig. 10, due to centrifugal member is then driven by the driving member through. the impelling spring 20 without appreciable retardation. lit, on the other hand, the engine should fail to start into operation under its own power, or its speed does not rise above the predetermined value, the nose 24: of the other locking element will, upon movement of the driven member through 180, come into engagement with the abutment 26, and the operation previously described is then repeated. The impelling movement may be repeated as often as needed at the successive ignition periods of the magneto.

Whenever the spring breaks, the looking elements are retained in their outermost position by the releasing cams 28, even though the speed of the engine is below the predetermined value.

if the direction of" rotation of the shaft 17 necessitates anticlockwise rotation of the coupling, the abutment 26 is seated on its other seat in which the screw t0 passes through the elongated opening 42 and the the slots 37 and 38. So also, the spring 20 is turned over and the pin 45 is seated in the hole 44. These parts then have the position illustrated in Fig. '11, the other parts having the same location as before. The cycle of operation of the impulse coupling in anticlockwise direction is then the same as that previously described for clockwise direction. lit will bebbserved, however, that inasmuch as the driven member 3 is keyed in a fixedangular position to the magneto shaft 2, irrespective of the direction of rotation, the magneto is locked in one angularposition for rotation in one direction and in another angular position (represented substantially by the angular extent or" the nose 2 1) for rotation in the reverse direction. in both cases, the magneto is locked prior to its period of maximum generation, in which the armature poles substantially bridge the field interpolar space, and is substantially impelled by the spring beyond that position.

laving now described our what we claim is:

i. in an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed angular displacement oi said memcentritugally-responsive looking mechoch driven member "is the driving member invention,

oers;

nism adapt-ed to l 1st rotation w l speed; and mechanism for the loci mechanism, when position at the driviven. men.

force. The drivenslowly and to be inoperative at ill) mechanism consisting of two Cooperative elements which, at low speed in one direction of rotation, are relatively positioned to engage each other in one angular position of the driven member and which, at low speed in the reverse, direction of rotation, are relatively positioned to engage each other at another angular position of the driven member.

2. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; contrifugally-responsive locking mechanism adapted to lock the driven mem ber against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the locking mechanism, when locked, at an advanced-position of the driving member relatively to the driven member; the centlrifugally-responsive locking mechanism consisting of two cooperative elements, one of which is located in one position for rotation of the coupling in one direction and is located in a second position for rotation in the opposite direction.

3. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular, displacement of said members; locking; mechanism adapted to lock the driven member against rotation while the driving member is rotating slowlyand tobe inoperative at higher speed; and releasing mechanism for releasing the locking: mechanism, when locked, at an advanced position of the driving member relatively to the driven member; the locking mechanism consisting of a centrifugally-responsive element, and an abutment which, during low speeds of rotation of said driving member, is engaged on oneface, when located in a selected one of two positions, in one direction of rotation of said driving member, and on the opposite face, when located in the other of said positions, in the opposite direction of rotation of said driving member.

In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said memhere; locking mechanism adapted to lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the locking mechanism, when locked, at an advanced position of the driving member relatively to the driven member; the locking mechanism consisting of a centrifugally-responsive element, and an abutment which is seated in one position for rotation in one direction and in another position for rotation in the es reverse direction .ingmechanism, when locked, at

5. In an impulse coupling, a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism adapted to lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the looking mechanism, when locked, at an advanced position of the driving member relatively to the driven member; the locking mechanism consisting of a centrifugally-responsive element,,a stationary plate having two seats, and an abutment fastened on one of said seats for cooperation with the 'centrifugallyresponsive element in one direction of rota tion and on the other of said seats for cooperation with the centrifugally-responsive element for rotationin the reverse direction.

In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism adapted to lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the lock an advanced position of the driving member relatively to the driven member; the locking mechanism consisting of a centrifugally-responsive element, a stationary plate having two seats, and an abutment fastened on one of said seats for cotiperation with the centrifugallyresponsive element in one direction of rotation and on the other of said seats with its opposite face arranged for cooperation with the centrifugally-responsive element for rotation in the reverse direction.

In an impulse coupling; a rotatable driving member; a rotatable driven member; a spiral impelling spring having its convolutions extending in anticlockwise direction for clockwise rotation and extending in clockwise direction for anticlockwise rotation; centrifugally responsive locking mechanism adapted to lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the locking mechanism, when locked, at an advanced position of the driving member relatively to the driven member; the centrifugally-responsive locking means consisting of two cooperative elements which, for rotation in one direction, are positioned to engage each other at low speed at one angular position of the driven member and which, for rotation in the reverse direction, are relatively positioned to engage each other at low speed at another angular position of the driven member.

8. ii an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism comprising locking means transversely slidable at low speed in response to gravity and at high speed in response to centrifugal action, and an abutment arranged axially adjacent said locking means to be engaged by the locking means at low speed and to be cleared thereby at higher speed; and releasing mechanism for releasing the locking mechanism, when locked, at an advanced position of the driving member relatively to the driven member; said locking mechanism being constructed and arranged to lock the driven member more than once per rotation at low speed.

9. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism comprising two elements each transversely slidable at low speed in responseto gravity and at high speed in response to centrifugal action,- and an abutment arranged to be engaged by both locking elements at low speed and to be cleared thereby at ing mechanism for releasing the locking elements from engagement with the abutment.

10. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism comprising two diametrically-disposed locking elements each transversely slidable at low speed in response to gravity and at high speed in response to centrifugal action, and an abutment arranged to be'engaged by both looking elements at low speed and to be cleared thereby at higher speed ;-and releasing mechanism for'releasing the locking elements from engagement with the abutment.

11. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; a transversely-slidable element responsive at low s 396d to gravity and at high speed to centrifugal force, and being arranged substantially entirely on one side of a plane containing the axis of rotation; an abutment arranged to be engaged by the locking element at low speed and to be cleared thereby at liigher speed; and releas ing mechanism for releasing the locking element i'rom engagement with the abutment.

12. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; two diametrically-disposed transversely-slidable elements each responsive at higher speed; and releaS- low speed to gravity and at high speed to centrifugal force, and each being arranged substantially entirely on one side of a plane containing the axis of rotation; an abutment arranged to be engaged by the locking elements at low speed and to be cleared thereby at higher speed; and releasing mechanism for releasing the locking elements from engagement with the abutment.

13. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; a centrifugally-responsive locking element; an abutment arranged to be engaged by the locking element to lock the driven member while the driving member is rotating slowly and to be cleared thereby at higher speed; releasing mechanism for releasing the locking element from engagement with the abutment; and mechanism constructed and arranged to retain the locking element in released position after the impelling spring breaks.

14. In an impulse coupling, a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; a centrifugally-responsive locking element; an abutment arranged to be engaged by the locking element to lock the driven member while the driving member is rotating slowly and to be cleared thereby at higher speed; releasing mechanism for releasing the locking element from engagementwith the abutment; and" mechanism constructed and arranged to retain the releasing mechanism in engagement with the locking element to hold it in released position after the impelling spring breaks.

15. In an impulse coupling; a rotatable driving member; a rotatable driven memher; an impelling spring arranged to be stressed upon angular displacement of said members; centrifugally-responsive locking mechanism arranged to lock the driven member against rotation while the driving member is rotating slowly and being inoperative at higher speed; releasing mechanism for releasing the locking mechanism, when locked, at an advanced position of the driving member relatively to the driven member; and cooperative members carried by the driving and driven members and adapted to engage each other, after the impelling spring breaks, at substantially said advanced position of the driving member; said cooperative members, when engaged, locking the driv'ng and driven members in such angular relation that the releasing ber; an impelling spring arranged to be table members having a stop' and the other stressed upon, angular displacement of said members; a centrifugally-responsive locking element; an abutment arranged to be engaged by said element to lock the driven member while the driving member is rotating slowly and to be cleared thereby at higher speed; releasing mechanism for releasing the locking element from engagement with the abutment; a stop carried by the driven member; and a pin carried by the driving member in position toengage said stop when the releasing mechanism engages the locking element and after the spring breaks.

17. In an impulse coupling;-a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; a centrifugally-responsive looking element; an abutment arranged to be engaged by said element to lock the driven member while the driving member is rotating slowly and to be cleared thereby at higher speed; releasing mechanism for releasing the locking element from engagement with the abutment; one of said rotahaving-two seats; a pin mounted on one of said seats for rotation in one" direction to gage said stop when the releasing mechanism engages the locking element, and mounted on/the other of said seats for rotation in'the reverse direction to engage said stop when the releasing mechanism engages the locking element.

18. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement'of said members; locking mechanism comprising a rotatable part and a coiiperative abutment; a stationary support for supporting the abutment in proximity to one of said members and within the periphery of said driven member; adjustable means for adjusting the support toward and from the member with which it is in proximity; and releasing mechanism for releasing the locking mechanism.

19. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacementofsaid members; locking mechanism comprising a rotatable element and cotiperative abutments; a stationary support for supporting the abutment in proximity to one of said members and within the periphery of said driven member; and a which the stationary support is secured, at least one of said posts being adjustable in length to move the support toward and from the member to which it is in proximlty.

20. In an impulse coupling, a rotatable driving member; a rotatable driven memplurality of posts to her; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism comprising a rotatable element and cooperative abutments; a stationary support for supporting the abutment in proximity to one of said members and within the periphery of said driven member; and a plurality of posts to which the stationary support is secured, all of said posts being adjustable in length to move the support toward and from the member to which it is in proximity.

21. In an impulse coupling; a rotatable driving member; a rotatable driven memher; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism adapted to lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the looking mechanism; said locking mechanism in cluding an axially related support and an abutment haying a plurality of legs engaging the support for distributing the force of impact thereto.

22. In an impulse coupling; a rotatable driving member; a-rotatable driven member; animpelling spring arranged to be stressed upon angular. displacement of said members; locking mechanism arranged to lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the locking mechanism; said locking mechanism including an axially related perforated support and an abutment having a plurality of legs set into said perforations to distribute the force of impact to the support.

23. In an impulse coupling; a rotatable driving member; a rotatable driven mem-- ber; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism arranged to. lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the locking mechanism; said locking mechanism including a support, an abutment having a plurality of legs engaging the support for distributing the force of impactthereto, and adjustable connecting means between the abutment and support.

24. In animpulse coupling; a rotatable driving member; a. rotatable driven memher; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism arranged to lock the driven member against rotation while the driving member is rotating slowly and to be inoperative at higher speed; and releasing mechanism for releasing the looking mechanism; said locking mechanism ineluding a support with two seats, and an abutment arranged to be seated on one of said seats for rotation of the driving member in one direction and to be seated on the other of said seats for rotation of the driving member in the reverse direction.

25. In an impulse coupling; a rotatable driving member; a rotatable driven member; an impelling spring arranged to be stressed upon angular displacement of said members; locking mechanism arranged. to lock the driven member against rotation while the driving member is rotatingslowly and to be inoperative at higher speed; and releasing mechanism for releasing the looking mechanism; said locking mechanlsm including a support having three circularlydisposed openings the center one of which is of greater angular extent than either of the others, and an abutment having two terminal legs adapted to be seated in the central opening and either one of the other openings.

In witness whereof, we afiix our signatures.

WOLFGANG E. SCHWARZMANN. CHARLES F. TOREN. 

